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[PATCH v3] media: videobuf2: forbid remove_bufs when legacy fileio is active

Marek Szyprowski posted 1 patch 3 months, 2 weeks ago
There is a newer version of this series
drivers/media/common/videobuf2/videobuf2-v4l2.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
[PATCH v3] media: videobuf2: forbid remove_bufs when legacy fileio is active
Posted by Marek Szyprowski 3 months, 2 weeks ago 
vb2_ioctl_remove_bufs() call manipulates queue internal buffer list,
potentially overwriting some pointers used by the legacy fileio access
mode. Add a vb2_verify_memory_type() check symmetrical to
vb2_ioctl_create_bufs() to forbid that ioctl when fileio is active to
protect internal queue state between subsequent read/write calls.

CC: stable@vger.kernel.org
Fixes: a3293a85381e ("media: v4l2: Add REMOVE_BUFS ioctl")
Reported-by: Shuangpeng Bai<SJB7183@psu.edu>
Suggested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/media/common/videobuf2/videobuf2-v4l2.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index d911021c1bb0..a8a5b42a42d0 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -1000,13 +1000,15 @@ int vb2_ioctl_remove_bufs(struct file *file, void *priv,
 			  struct v4l2_remove_buffers *d)
 {
 	struct video_device *vdev = video_devdata(file);
-
-	if (vdev->queue->type != d->type)
-		return -EINVAL;
+	int res;
 
 	if (d->count == 0)
 		return 0;
 
+	res = vb2_verify_memory_type(vdev->queue, vdev->queue->memory, d->type);
+	if (res)
+		return res;
+
 	if (vb2_queue_is_busy(vdev->queue, file))
 		return -EBUSY;
 
-- 
2.34.1
Re: [PATCH v3] media: videobuf2: forbid remove_bufs when legacy fileio is active
Posted by Marek Szyprowski 3 months, 2 weeks ago 
On 23.10.2025 13:30, Marek Szyprowski wrote:
> vb2_ioctl_remove_bufs() call manipulates queue internal buffer list,
> potentially overwriting some pointers used by the legacy fileio access
> mode. Add a vb2_verify_memory_type() check symmetrical to
> vb2_ioctl_create_bufs() to forbid that ioctl when fileio is active to
> protect internal queue state between subsequent read/write calls.
>
> CC: stable@vger.kernel.org
> Fixes: a3293a85381e ("media: v4l2: Add REMOVE_BUFS ioctl")
> Reported-by: Shuangpeng Bai<SJB7183@psu.edu>
> Suggested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---

History:

v3:
- moved vb2_verify_memory_type() check after (d->count == 0) check to 
pass v4l2
  compliance

v2: 
https://lore.kernel.org/all/20251020160121.1985354-1-m.szyprowski@samsung.com/
- dropped a change to vb2_ioctl_create_bufs(), as it is already handled
   by the vb2_verify_memory_type() call
- replaced queue->type check in vb2_ioctl_remove_bufs() by a call to
   vb2_verify_memory_type() which covers all cases

v1: 
https://lore.kernel.org/all/20251016111154.993949-1-m.szyprowski@samsung.com/

>   drivers/media/common/videobuf2/videobuf2-v4l2.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index d911021c1bb0..a8a5b42a42d0 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -1000,13 +1000,15 @@ int vb2_ioctl_remove_bufs(struct file *file, void *priv,
>   			  struct v4l2_remove_buffers *d)
>   {
>   	struct video_device *vdev = video_devdata(file);
> -
> -	if (vdev->queue->type != d->type)
> -		return -EINVAL;
> +	int res;
>   
>   	if (d->count == 0)
>   		return 0;
>   
> +	res = vb2_verify_memory_type(vdev->queue, vdev->queue->memory, d->type);
> +	if (res)
> +		return res;
> +
>   	if (vb2_queue_is_busy(vdev->queue, file))
>   		return -EBUSY;
>   

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland
Re: [PATCH v3] media: videobuf2: forbid remove_bufs when legacy fileio is active
Posted by Hans Verkuil 3 months, 2 weeks ago 
On 23/10/2025 13:30, Marek Szyprowski wrote:
> vb2_ioctl_remove_bufs() call manipulates queue internal buffer list,
> potentially overwriting some pointers used by the legacy fileio access
> mode. Add a vb2_verify_memory_type() check symmetrical to
> vb2_ioctl_create_bufs() to forbid that ioctl when fileio is active to
> protect internal queue state between subsequent read/write calls.
> 
> CC: stable@vger.kernel.org
> Fixes: a3293a85381e ("media: v4l2: Add REMOVE_BUFS ioctl")
> Reported-by: Shuangpeng Bai<SJB7183@psu.edu>
> Suggested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  drivers/media/common/videobuf2/videobuf2-v4l2.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index d911021c1bb0..a8a5b42a42d0 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -1000,13 +1000,15 @@ int vb2_ioctl_remove_bufs(struct file *file, void *priv,
>  			  struct v4l2_remove_buffers *d)
>  {
>  	struct video_device *vdev = video_devdata(file);
> -
> -	if (vdev->queue->type != d->type)
> -		return -EINVAL;
> +	int res;
>  
>  	if (d->count == 0)
>  		return 0;

Ah, no. This should still check d->type. So:

	if (d->count == 0)
		return d->type == vdev->queue->type ? 0 : -EINVAL;

Regards,

	Hans

>  
> +	res = vb2_verify_memory_type(vdev->queue, vdev->queue->memory, d->type);
> +	if (res)
> +		return res;
> +
>  	if (vb2_queue_is_busy(vdev->queue, file))
>  		return -EBUSY;
>
Re: [PATCH v3] media: videobuf2: forbid remove_bufs when legacy fileio is active
Posted by Marek Szyprowski 3 months, 2 weeks ago 
On 23.10.2025 13:36, Hans Verkuil wrote:
> On 23/10/2025 13:30, Marek Szyprowski wrote:
>> vb2_ioctl_remove_bufs() call manipulates queue internal buffer list,
>> potentially overwriting some pointers used by the legacy fileio access
>> mode. Add a vb2_verify_memory_type() check symmetrical to
>> vb2_ioctl_create_bufs() to forbid that ioctl when fileio is active to
>> protect internal queue state between subsequent read/write calls.
>>
>> CC: stable@vger.kernel.org
>> Fixes: a3293a85381e ("media: v4l2: Add REMOVE_BUFS ioctl")
>> Reported-by: Shuangpeng Bai<SJB7183@psu.edu>
>> Suggested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>>   drivers/media/common/videobuf2/videobuf2-v4l2.c | 8 +++++---
>>   1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> index d911021c1bb0..a8a5b42a42d0 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>> @@ -1000,13 +1000,15 @@ int vb2_ioctl_remove_bufs(struct file *file, void *priv,
>>   			  struct v4l2_remove_buffers *d)
>>   {
>>   	struct video_device *vdev = video_devdata(file);
>> -
>> -	if (vdev->queue->type != d->type)
>> -		return -EINVAL;
>> +	int res;
>>   
>>   	if (d->count == 0)
>>   		return 0;
> Ah, no. This should still check d->type. So:
>
> 	if (d->count == 0)
> 		return d->type == vdev->queue->type ? 0 : -EINVAL;

Then frankly speaking lets get back to v1 limited to 
vb2_ioctl_remove_bufs(), as using vb2_verify_memory_type() in this 
context only makes things harder to understand:

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c 
b/drivers/media/common/videobuf2/videobuf2-v4l2.c index 
d911021c1bb0..f4104d5971dd 100644 --- 
a/drivers/media/common/videobuf2/videobuf2-v4l2.c +++ 
b/drivers/media/common/videobuf2/videobuf2-v4l2.c

@@ -1010,6 +1015,11 @@ int vb2_ioctl_remove_bufs(struct file *file, void 
*priv, if (vb2_queue_is_busy(vdev->queue, file)) return -EBUSY; + if 
(vb2_fileio_is_active(vdev->queue)) { + dprintk(vdev->queue, 1, "file io 
in progress\n"); + return -EBUSY; + } + return 
vb2_core_remove_bufs(vdev->queue, d->index, d->count); } 
EXPORT_SYMBOL_GPL(vb2_ioctl_remove_bufs);


> Regards,
>
> 	Hans
>
>>   
>> +	res = vb2_verify_memory_type(vdev->queue, vdev->queue->memory, d->type);
>> +	if (res)
>> +		return res;
>> +
>>   	if (vb2_queue_is_busy(vdev->queue, file))
>>   		return -EBUSY;
>>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland
Re: [PATCH v3] media: videobuf2: forbid remove_bufs when legacy fileio is active
Posted by Hans Verkuil 3 months, 2 weeks ago 
On 23/10/2025 13:55, Marek Szyprowski wrote:
> On 23.10.2025 13:36, Hans Verkuil wrote:
>> On 23/10/2025 13:30, Marek Szyprowski wrote:
>>> vb2_ioctl_remove_bufs() call manipulates queue internal buffer list,
>>> potentially overwriting some pointers used by the legacy fileio access
>>> mode. Add a vb2_verify_memory_type() check symmetrical to
>>> vb2_ioctl_create_bufs() to forbid that ioctl when fileio is active to
>>> protect internal queue state between subsequent read/write calls.
>>>
>>> CC: stable@vger.kernel.org
>>> Fixes: a3293a85381e ("media: v4l2: Add REMOVE_BUFS ioctl")
>>> Reported-by: Shuangpeng Bai<SJB7183@psu.edu>
>>> Suggested-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>>> ---
>>>   drivers/media/common/videobuf2/videobuf2-v4l2.c | 8 +++++---
>>>   1 file changed, 5 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> index d911021c1bb0..a8a5b42a42d0 100644
>>> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
>>> @@ -1000,13 +1000,15 @@ int vb2_ioctl_remove_bufs(struct file *file, void *priv,
>>>   			  struct v4l2_remove_buffers *d)
>>>   {
>>>   	struct video_device *vdev = video_devdata(file);
>>> -
>>> -	if (vdev->queue->type != d->type)
>>> -		return -EINVAL;
>>> +	int res;
>>>   
>>>   	if (d->count == 0)
>>>   		return 0;
>> Ah, no. This should still check d->type. So:
>>
>> 	if (d->count == 0)
>> 		return d->type == vdev->queue->type ? 0 : -EINVAL;
> 
> Then frankly speaking lets get back to v1 limited to 
> vb2_ioctl_remove_bufs(), as using vb2_verify_memory_type() in this 
> context only makes things harder to understand:
> 
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c 
> b/drivers/media/common/videobuf2/videobuf2-v4l2.c index 
> d911021c1bb0..f4104d5971dd 100644 --- 
> a/drivers/media/common/videobuf2/videobuf2-v4l2.c +++ 
> b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> 
> @@ -1010,6 +1015,11 @@ int vb2_ioctl_remove_bufs(struct file *file, void 
> *priv, if (vb2_queue_is_busy(vdev->queue, file)) return -EBUSY; + if 
> (vb2_fileio_is_active(vdev->queue)) { + dprintk(vdev->queue, 1, "file io 
> in progress\n"); + return -EBUSY; + } + return 
> vb2_core_remove_bufs(vdev->queue, d->index, d->count); } 
> EXPORT_SYMBOL_GPL(vb2_ioctl_remove_bufs);

I agree. Can you post a v4?

Regards,

	Hans

> 
> 
>> Regards,
>>
>> 	Hans
>>
>>>   
>>> +	res = vb2_verify_memory_type(vdev->queue, vdev->queue->memory, d->type);
>>> +	if (res)
>>> +		return res;
>>> +
>>>   	if (vb2_queue_is_busy(vdev->queue, file))
>>>   		return -EBUSY;
>>>
> Best regards

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